The FDA Just Approved a New Prescription Weight-Management Device. Here’s How It Works

In a rare move, the Food and Drug Administration (FDA) has approved a novel prescription device meant to help with weight management.

The product, called Plenity and developed by Gelesis, has been cleared for overweight or obese adults with a body mass index of at least 25, even if they do not have other health problems. It should be used in conjunction with diet and exercise, the FDA says, and can also be taken alongside other weight-loss medications.

That sweeping approval is noteworthy, says Dr. Caroline Apovian, who has studied Plenity in Gelesis-sponsored research and is the director of nutrition and weight management at Boston Medical Center, because most weight-loss treatments are available only to patients with a BMI of 30 or above, or who have other weight-related health issues. “Right now, between a BMI of 25 and 30 we have a big treatment gap. If you’re overweight and you have no [other issues]…all we have to offer is lifestyle,” Apovian says. “Now, there is a treatment.”

It has traditionally been difficult to find science-backed, non-surgical weight-loss aids that work. The FDA has approved only five prescription weight-loss drugs, and has repeatedly warned consumers against taking products claiming they can cause weight-loss “miracles.” Over-the-counter dietary supplements promising weight loss — which are not regulated by the FDA — also tend to be ineffective at best, and unsafe or tainted at worst. Even some FDA-approved weight-loss drugs have been pulled from the market because of safety issues.

Previously approved weight-loss drugs typically work by targeting the brain to suppress appetite or simulate feelings of fullness. Plenity, by contrast, helps fill the stomach when taken before a meal. Each pill contains a mix of cellulose and citric acid, which, when hydrated in the stomach, expands to form a hydrogel with the consistency of chewed food. The capsules can fill about a quarter of the stomach without contributing any calories, helping people feel full from eating less, according to the company. The gel then passes through the digestive system just like regular food.

“It creates a sense of satiety, but it’s not a compound that enters the bloodstream and goes to the brain,” Apovian says. “In that respect, it’s so unique because it’s actually benign and safe, in terms of side effects that can cause issues centrally. It’s a very safe, low-risk alternative.”

Pricing information is not yet available. A Gelesis representative tells TIME that the company is “committed to making sure Plenity is affordable for consumers out-of-pocket, even if their insurance does not cover it.” A limited launch of the device is expected during the second half of this year, with widespread availability slated for 2020, Gelesis says.

Gelesis says the device has been shown to help people lose an average of 10% of their body weight in six months. In one Gelesis-sponsored study, which was published in the journal Obesity last fall, researchers including Apovian found that people taking Plenity had twice the odds of losing 5% or 10% of their body weight over six months, compared to people taking a placebo. Plenity seemed to be particularly effective for people with elevated fasting blood glucose levels and prediabetes, according to the study.

The most common side effects reported in the Obesity study were gastrointestinal symptoms. The device should not be used by pregnant women, people who are allergic to the device’s contents, those with esophageal abnormalities or strictures or individuals with complications from previous gastrointestinal tract surgeries. People with active gastrointestinal issues and those taking certain prescription drugs should also use caution, the company says.

Primary care doctors typically recommend that people who want to lose weight start with lifestyle adjustments, such as moving more and eating healthfully, and Apovian calls these the cornerstones of weight management. But given that more than 70% of American adults are overweight or obese, and about half of American adults say they’re trying to shed pounds, regulated weight-loss treatments can provide a valuable second strategy.

Correction, April 16

The original version of this story misstated the terms of Plenity’s FDA approval. It was cleared as a device for weight management, not a drug for weight loss.